Apparatus for the reproduction of sounds telephonically



m 15, 1929- c. s. BABCOCK 1,709,201

APPARATUS FOR THE REPRODUCTION OF SOUNDS TELEPHONICALLY Filed May 1, 1922 5 Sheets-Sheet 1 April 16, 1929'. c s. BABcocK APPARATUS FOR THE REPRODUCTION OF SOUNDS TELEPHONJICQLLY FiledMay 1. "1922 6 Sheets-Sheet WWN Patented Apr. 16, 1929.

UNITED STATES CHARLES S. BABCOCK, OF OAK PARK, ILLINOIS.

APPARATUS FOR THE REPRODUCTION OF SOUNDS TELEPHONICALLY.

Application fil'ctl May 1, 1922. Serial No. 557,665.

My invention relates to the reproduction of sounds, and has for a primary object to provide novel and improved means whereby a. more accurate telephonic reproduction of sounds both as to pitch and timbre may be obtained than is possible with the apparatuses heretofore available.

A further object of the invention is to provide new and improved means for amplifying and intensifying the current undulations in the telephonic circuit or circuits employed so as to increase the volume of the sounds produced by the apparatus.

A further object is to construct the motive instrument (or instruments), that is, the instrument which translates the current undulations into mechanical vibrations so that it will be operated magnetically in both directions instead of being dependent upon the elastic reaction of a diaphragm for its movements in one direction as is usual in mechanisms of this class.

With reference to the part of the apparatus for producing the sonorous vibrations, my

r invention contemplates an arrangement of several musical instruments of difierent pitches and timbres, for example, both string and wind instruments or other bodies capable of vibrating sonorously, which are connected to or operated by an actuating member or structure that is caused to vibrate or oscillate by any suitable means, for example, by a device responsive to the current pulsations of a telephonic circuit, the value and utility of this feature of the invention being based upon the discovery which I have made that each of these several musical instruments will respond selectively to certain of these vibrations, and resonate accordingly, but will not respond to other vibrations so long as there are other instruments capable of responding to such other vibrations. That is to say, the violin, for example, will respond, appreciably at least, only to the vibratory movements of the actuating member corresponding to sounds within the normal range and timbre of the violin; and the same is true with the other stringed instruments, and with the brasses and the wood winds, each of which will select its own appropriate vibrations. However, this selective action takes place only in case a number of instruments of different character are operated on simultaneously by the same series'of vibrations. If one instrument alone is acted upon by all of the vibrations it will respond not only to vibrations within its own proper range but also, although inadequately, to the vibrations outside of its range, with the result that reproduction is incomplete and the tones emitted impure.

A further object of the invention is to provide a novel mechanism for reproducing sound from a phonograph record by utilizing the vibrations of the phonograph stylus for the production of a telephonic current or currents, the undulations of which are (preferably after being amplified) translated into sonorous vibrations by means of an electromagnetic vibratory motor.

A further object of the invention is to provide the apparatus with insulating or vibration damping elements at such places as may be necessary in order to prevent the vibrations intended to be transmitted, namely, the longitudinal oscillatory movements of the members operated by the phonograph stylus or by the telephonic transmitter and by the magnets employed in amplifying the telephonic currents and in translating their undulations in to sonorous vibrations, from being affected or contaminated by vibrations set up in other parts of the apparatus or by those set up accident-ally in the oscillatory members themselves due to the connection of said members with other parts of the apparatus. This insulation is particularly important where, as in the apparatus shown herein, the vibrations produced by the phonograph stylus or other means, are divided, so to speak, and impressed in the form of undulations of complementary character on two currents designed to act in opposite senses upon a vibratory magnetic motor. Under these conditions unless the corresponding undulations of the two telephonic currents 'are exactly alike (except that one represents increase and the other proportionate decrease in current intensity) one current will neutralize the other to a greater or less extent at least.

A further object of the invention is to provide a telephone transmitter capable of producing sinmltancously two telephonic currents, the corresponding undulations of which are of like amplitude but opposite phase, through the vibration in opposite direction of the diaphragm or other element sensitive to sound Waves. This device may be used, in connection with the vibratory motor acting upon the resonant body or bodies, in place of the mechanism above referred to for producing the telephonic currents through phonograph; record in accordance with the principles of my invention.

Fig. 2 is a detail viewto illustrate the means employed for operatively connecting a brass instrument, such as a horn or trumpet, to the vibratory motor. I

Fig. 3 is afragmentary side elevation, with parts in section, showingv one end of the amplifying mechanism;

Fig. 4 is a. fragmentary plan view of the amplifying mechanism.

Fig. 5 is a longitudinalsectional view i1lus trating a telephone transmitting device for producing, simultaneously, two telephonic currents of complementary character.

v Fig. ,6 is alongitudinal sectional view on line 6-6 of Fig. 5. 1

Referring first to Figs. 1 and 2 of the drawing, A designates, as a whole, the mechanism for impressing upon telephonic currents, undulations corresponding to the oscillations of the phonograph stylus.

B designates, as a whole, the mechanism for amplifying the current undulations produced by mechanism A.

C designates, as a whole, the mechanism for translating the current undulations amplified by mechanism B into sonorous vibrations.

The mechanism A is preferably constructed as follows: 10 is a phonograph stylus and 11 the record for oscillating the same. The needle is shown as oscillating-laterally but the mechanism can be readily adapted so as to dperate upon a record of the hill and dale type. The stylusis carried by an arm or needle holder 12 pivoted at 13 to one of the members 14 of a frame structure or head 15 arranged on a lever 16 fulcrumed on knife edges at 17 and provided with a counterpoise 18 which in practice shouldbe capable of adjustment to obtain the correct pressure of the needle on the record. 19 is a flexible strip to which the upper end of the needle holder 12 is attached, the strip extending between member 14 and member 20 of the head 15. 21 is a rod connected with the strip 19'and interposed'between a pair of oppositely disposed telephone transmitting devices, preferably microphone transmitters 22, 23, which are arran ed on members24, 25 forming a part of the 'ead 15 and united to the head by one or more cross rods 26.

The stylus 10, when oscillated on pivot 13, operates through rod 21 to impress upon each 0 the currents controlled by the microphones rest, while the resistance of circuit 28 of microphone 23 will be proportionately increased to produce a proportionate diminu:

tion of current. The undulation in circuit 27 may, therefore, be said to be in the ascending phase and that of circuit 28 in the descendphase. Similarly when the upper end of the needle holder 12 moves-t0 the left the resistance ofthecircuitof microphone23 will be decreased and the resistance of the circuit of microphone 22 increased proportionately. The simultaneously produced wavesin thetwo circuits are of the same amplitude. One involves a diminution of current intensity, the other an increase. The effect is, so to speak, to divide the vibrations of the phonograph stylus into two antithetical or complementary telephonic currents. That these currents are antithetical or complementary may be shown by connecting them with a single telephone receiver, in which case no sounds, or at least no intelligible sounds, will be produced. The batteries of circuits 27 and 28 are indicated at 29 and 30. Each of these circuits preferably contains the primary coils being designated 31, 32. Their secondary coils 33, 34 are arranged in circuits 35, 36 which will be described in connection with the description of mechanism B.

The amplifier referred to as mechanism B is preferably constructed as follows: 37, 38 designate a pair of opposed electro-magnets having an interposed armature 39, the magnets and their common armature constituting a double acting vibratory motor. As shown, the elector-magnet 37 comprises a pair of coils 40 in circuit 35 of the secondary coil of transformer 3l33 and a pair of coils 41, 41 permanently energized from battery 42 arranged in a circuit 43. Magnet 38 consists, similarly, of a pair of coils 44, 44 arranged in the circuit 36 of the secondary coil of transformer 32--34 and a pair of permanently excited coils 45, 45, the circuit of which is indicated at 46. The magnets 41, 45 may be permanent magnets.

It will be seen that, due to the difference of phase of the currents passing through circuits 35, 36,'armature 39 will be positively moved first in one direction and then in the other direction, the movements corresponding, therefore, to the oscillatory movements of the phonograph stylus. The armature 39 has connected therewith a rod 47 to opposite ends of which are attached plates 48, 49. These plates are provided witha plurality of rods 50 which bear against a corresponding number 'of telephone transmitting devices (preferably of the microphone type) at each side of the mechanism. the number of which will depend upon the degree of amplification required, those at the right hand side of the mechanism being designated 51 and those at the left hand side being designated 52. The microphones at the right-hand side of the mechanism control circuits designated 53, supplied with current from batteries 54 and containing the primary coils 55 of transformers, the secondary coils of which are designated 56 and are'connected in multiple with each other. The microphones 52 on the left hand side of the mechanism control circuits 57 supplied with current from batteries 58 and containing the primary coils 59 of transformers, the secondary coils of which are designated 60 and are connected in-circuit with each other. I

It will be understood that I have shown a plurality of batteries throughout the drawing for the purpose of simplifying the wiring. All of the circuits requirin direct current might be supplied from a single battery by suitable wiring arrangements.

The mechanism C for translating the amplified telephonic currents produced as above described into sonorous vibrations is preferably constructed as follows: 61, 62 designate a pair of oppositely arranged magnets provided with an interposed armature 63, the magnets having preferably the same construction as magnets 37, 38 of the amplifying mechanism. The forward coil 64 of mag net 61 is arranged in a circuit 65 containing the secondary coils 56 of the transformers 55-56. The rear coils 66 are permanently energized from battery 67, the circuit being indicated at 68V Similarly the forward coils 69 of magnet 62 are in a circuit 70 containing the secondary coil 60 of the transformers 59-60. The rear coils 71 of magnet 62 are permanently energized from battery 67, the circuit being indicated at 72. Armature 63 carries a rod 73 one end of which is operatively connected with a plurality of stringed instruments of different pitch, while the other end is operatively connected with a plurality of wind instruments of different character, for example. to a plurality of brass instruments of different pitch. I have indicated the left hand end of the rod 73 as attached to the bridges of a bass violin 74, a Violoncello 75 and two violins 76. The other end of the rod is shown as operatively connected with a bass tuba 77, a trombone 78 and a trumpet 79. The-number and species of musical instruments thus coupled up for simultaneous actuation may, of course, be varied. For connecting the brass instruments to the rod a flexible diaphragm 80 is arranged in the mouthpiece of the instrument, as indicated in Fig. 2, to which the rod is attached, the rod being provided with yokes 81 which extend around the mouthpieces of all but the last of the instruments. The instruments of lower pitch are arranged nearer the armature.

It is a matter of very cqnsiderable importance if accurate reproduction of sound is to. be obtained, that the vibratory movements of the several elements of the apparatus which are intended to vibrate should not be affected by any incidental vibrations of the other parts of the apparatus or by vibrations set up in said elements other than the straight forward or back oscillations of said elements. In mechanism A the vibrations of rod 21 should correspond accurately with the vibratory movements of the phonograph stylus. The rod 21 is. therefore, shown as made in sections with damping elements 82 of felt, or the like. interposed between the sections, and the head 15 is throughout of laminated construction with damping elements, indicated at 83, between the laminations. The rod or rods 26 connecting members 24 with the head are made in sections with interposed insulating elements 84.

In the amplifyin 7 mechanism B the vibratory movements 0 rod 47 should be transmitted without contamination by foreign vibrations to the microphones 51, 52. Likewise the vibrations of microphones 51 and 52 should not inter-mingle with each other.

In Figs. 3 and 4 I have shown parts of the amplifying mechanism and its mounting for the purpose, particularly, of illustrating the means preferably employed for damping or cutting ofi' vibrations likely, if not checked. to interfere with the proper functioning of the mechanism. In these figures the magnets 37 are shown as secured to the upright member 85 of a chair 86 movable. for adj ustment, on a plate 87, a structure consisting of a table 88, uprights 89 and side rails 90. Vibration insulation, of felt, for example, is interposed at 91 between the table 88 and the base plate 89, the plate being held on the table by bolts 92 which pass through enlarged openings 93 in the table. A felt washer 94 is interposed between the table and the metal washer 95 that is arranged under the nut 96 on bolt 92. The insulating or damping element 97 is interposed between the upright 85 and the plate 98 to which magnets 37 are attached. Damping elements 99 are interposed between the late 98 and strips 190 through which extend the screws 191v for attaching plate 98 to the upright 85. The diaphragm 102 carrying the common armature 39 of magnets37, 38 is shown as clamped between a pair of clamping blocks 103. by means of screws 104 which extend through uprights 105 fastened to the side rail 90. The screws bearing against plates 106 between which and the block 103 are interposed damping elements 107. The rod 47 is preferably supported.

ing element 115 is arranged on the opposite side of plate 48 against which bears the nut 116 on the end of rod 47. a

The microphones 51 are mountedon a plate 117 which is secured to but insulated from the side rails 90 in the manner indicated atthe right handend of Fig. 3. 118. 119, 120 are three metal strips between which are interposed pieces of felt insulation 121, 122. The strip 118 is secured to the side rail 90 by screw 123. The strips 119, 120 are secured to plate 117 by a screw 124 which passes through an enlarged opening 125 in the strip 120. 126 are screws passing through enlarged openings 127 in plates 118, 119 and having threaded engagements with strip 120. Felt bushings 128 are interposed between the heads of screws 126 and the strip 118.

Each of the push rods 50 for operating the microphones 51 is preferably made in sections with an'insulating element 129 interposed between the sections. Chair 86 is adjusted by means of an adjusting screw 130 threaded through a block 131 on the base plate 87 and engaging the bottom member 132 of the chair. The forward part of the chair is slotted as indicated at 133 for set screws 134. It will be understc-od that the other end of the mechanism shown in part in Figr 3 will be constructed in the same manner as the portion shown in that figure.

So far as the vibration and insulation is concerned. the mechanism which has been designated mechanism C may be constructed on the same principles as the amplifier shown in Figs. 3 and 4. In the diagrammatic view (Fig. 1) the rod 73 which corresponds with rod 4-7 of the amplifier is shown as made in sections with damping elements 135 interposed between the sections. The partial and somewhat schematic showing of the apparatus in the appended drawings does not permit of a detailed illustration of all of the means employed inan operative apparatus for insulating the parts one from another so as to preserve intact the vibrations intended to be transmitted and translated into sonorous wave movements. From the foregoing, however, it will be understood that in order to obtain the best results the construction of the apparatus should be such that the parts intended to vibrate should be protc'cted against vibrations of all the other parts of the apparatus notintended to vibrate in unison therewith by damping means of the character indicated. a

Summary of 0pemtz'on-.The vibratory movements of the phonograph needle 10 are transmitted by rod 21 to the microphones 22, 23 producing telephonic currents, the simultaneously produced undulations of which are of corresponding amplitude but of opposite phase. These two telephonic currents act on the electro-magnetic motor 37 38. producing two sets of telephonic currents, the currents of each set being identical, those of one set having undulations corresponding in amplitude but of opposite phase. These two telephonic currents energize the electro-magnetic motor 61-62 so as to move its armature 63 positively back and forth to vibrate rod 73 which, by its connection with the instruments 73 to 79, sets the instruments in vibration selectively, each instrument responding to vibrations within its own range.

I realize that the principles of my invention might be embodied in apparatus quite differently constructed from that shown and described. Therefore, I wish it to be understood that the invention covers all modifications of such apparatus within the scope of the appended claims.

In Figs. 5 and 6 I have shown a telephone transmitter which may be substituted in the mechanism shown in Fig. 1 for the phonographically actuated mechanism designated A. That is, my invention contemplates the production of the two complementary telephonic currents directly from sound waves as well as indirectly through the agency of a phonograph record. In Figs. 5 and 6, 136 designates the shell or casing of the transmitter and 137 the diaphragm or vibratory body sensitive to sound waves. Within the shell are arranged two microphones or carbon boxes 138, 139 which are placed back to back against a supporting structure comprising two plates 140, 141 and an interposed vibration insulating element 142. these parts being secured against shoulders 143 on the shell bv screws 144 properly insulated from the plates 140, 141. The microphones are connected with the diaphragm 137 by a yoke so that the movement inwardly of the diaphragm produces an inward movement to the plunger 145 of microphone 138 and an outward movement to the plunger 146 of microphone 139, while outward or return movement of the diaphragm'137 operates the microphones in the opposite sense. As a result the vibratory movements of the diaphragm impress upon the currents controlled by the may be amplified as previously described and utilized electro-magnetically for imparting vibrations in opposite directions to the resonant body or bodies. The yoke referred to for connecting the microphones to diaphragm 137 consists of a pair of heads 147, 1 18 connected with the microphone plungers by damping elements 149, and rods 150 connecting the heads with the interposition of damping elements 151.

I claim:

1. In combination with a pronograph stylus adapted to be oscillated mechanically, a vibratory magnetic motor comprising two opposed magnets and a singlearmature arranged between them andmechanism actu ated by the movements of said stylus in opposite directions for energizing said magnets simultaneously by telephonic currents corre sponding to the vibrations of said stylus,

the undulations of which are of correspond 1 ing amplitudes but of opposite phase.

2. In combination with a phonograph stylus adapted to be oscillated mechanically, a vibratory vmagnetic motor comprising two opposed magnets and a single armature arranged between them, a pair of telephone transmitters. to energize said magnets respectively, and a member interposed between the vibratory elements of said transmitters and connected with said stylus so as to be oscillated thereby.

3. In combination with a phonograph stylus adapted to be oscillated mechanically, a pair of telephone transmitters, mechanism whereby the movements of the stylus in opposite directions impress undulations of like amplitudes but opposite phase on the currents controlled by said telephone transmit-- ters, and a vibratory motor comprising two electro-magnets energized in correspondence with the undulations 'of said telephonic currents respectively, and an armature which vibrates between said magnets.

4:. In combination with a phonograph stylus, a pair of telephonic transmitters, mechanism whereby the movements of the stylus in opposite directions impress undulations of like amplitudes but opposite phase on the currents controlled by said telephonic transmitters, a vibratory motor comprising two electro-magnets energized in correspondence with the undulations of said telephonic currents respectively, an armature which vibrates between said magnets, and a resonant body set in vibration by the movements of said armature.

5. In combination with a phonograph stylus, a air oi telephone transmitters, mechanism whereby the movements of the stylus in opposite directions impress undulations of like amplitudes but opposite phase on the currents controlled by said telephone transmitters, a vibratory motor comprising two electro-magnets energized in correspondence with the undulations of said telephonic currents respectively, an, armature which vibrates-between saidmagnets, and mechanism actuated thereby for producing telephonic currents corresponding tov the aforesaid telephonic currents, respectively, butwith their undulations amplified.

6. In combination with a phonograph stylus, a pair of telephone transmitters, mecha nism whereby the movements of the stylus in opposite directions impress undulations of like amplitudes but opposite phase on the currents controlled by said telephone transmitters, a vibratory motor comprising two electro-magnets energized in correspondence with the undulations of said telephonic currents respectively, an armaturewhich vibrates between said magnets, mechanism actuated thereby for vproducing telephonic currents corresponding to the aforesaid telephonic currents, respectively, but with their undulations, amplified, and a vibratory magnetic motor comprising two electro-magnets and an armature arranged between said mag net-s being energized in correspondence with said amplified currents, respectively.

7 In combinationwith a phonograph stylus, a pair of telephone transmitters, mechanism whereby the movements of the stylus in opposite directions impress undulations of like amplitudes but opposite phase on the currents controlled by said telephone transmitters, a vibratory motor comprising two electro-magnets energized in correspondence with the undulations of said telephonic currents, respectively, an armature which vibrates between said magnets, imechanism actuated therebyfor producing telephonic currents corresponding to the aforesaid telephonic currents, respectively, but with their undulations amplified, a vibratory magnetic motor comprising two electro-magnets and an armature. arranged between said magnets being energized in correspondence with said amplified currents, respectively, and a resonant body'set in vibration by the movements of said armature. v

8. In combination with a musical instrument, ofmeans for setting, the same in vibration comprising a member operatively engaged with a vibrating portion of the instrument, an armature to which said memberQis attached, a pair of magnets between which said armature oscillates, and means for energizing said magnets by telephonic currents aving undulations of corresponding amplitude but opposite P1183561 9. In telephonic sound reproducing mechanism, the combination of an electro-magnet, means for energizing said ma net by telephonic currents, a plurality o musical instruments, an armature for said magnet, and a rod connected with saidarmature which operatively engages said instruments to vibrate the same sonorously;

10. In telephonic sound reproducing mechanism,'the combination of an electro-magnet, means for energizing said magnet by telephonic currents, a plurality of stringed and wind instruments, an armature for said magnet, and means for operatively connecting said armature to said instruments for causing said instruments to vibrate sonorously.

11-. In telephonic sound reproducing mechanism, the combination ofan electro-magnet, means for energizing said magnet by telephonic currents, an armature for said magnet, a member connected with said armature and extending on opposite sides of the same,

a plurality of stringed instruments operatively connected with one end of said member, and a plurality of wind instruments operatively connected with the other end of said member.

' I 12. In telephonic sound reproducing mechanism, the combination of an electro-magnet, means for energizing said magnet by telephonic currents, an armature for said magnet, a memberconnected with said armature and extending on opposite sides of the same,

a plurality of stringed instruments of different pitcli operatively connected with one end of said member, with the instruments of lower pitch nearer the-armature than those of higher pitch, and a plurality of Wind instruments of difierent pitch having vibrating elements operatively connected to the other end of said member and arranged with the instruments of lower pitch nearer the armature than those of higher pitch.

u said member.

13. In telephonic sound reproducing mechanism, the combination of an electro-magnet, means for energizing said magnet by telephonic currents, an armature for said magnet, 'afmember connected with saidfarmature,

a d pars y: i ra m s c iIistrumiits f difierentpitc'h operatively connected with. said memberfi'jf" 14. 'In t'elephonicsound reproducing mechani'sm', the combination of a pair' of oppositely 15. In mechanism for transmitting and reproducing sounds telephonically, the, co1nbination of a vibratory. element adapted to be vibrated mechanically, two, microphones connectedwith saidvibratory element so that i the vibrations of said element produce two telephonic currents of complementary charactor, and a reproducer comprising a resonant element and two electro-magnets for vibrating said resonant element in opposite directions which are energized in accordance with the undulations of said two telephonic currents, respectively. I

16. --In mechanism of the character described, the combination of means for imparting vibrations iii-opposite senses to two microphones to produce telephonic currents of complementary character, a resonant element, and two opposed magnets for vibrating the same in opposite directions, which magnets are energized simultaneously by said telephonic currents, respectively. 7

17. In mechanism of the character described, the coinbination of an electro-magnet, an armature, a flexible diaphragm carrying said armature, a support for said diaphragm, and vibration damping means interposed between said diaphragm and its suport. p 18. In sound reproducing mechanism, the combination of an electro-magnet, means for energizing said magnet by telephonic currents, an armature for said magnet, a plurality of stringed and brass musical instruments each adapted to respond selectively to certain vibrations, and means connecting said armature to said instruments for causing them to vibrate sonorously. a 19. In sound reproducing mechanism, the combination ofan electro-magnet, means for energizing said magnet by telephonic currents, an armature for said magnet, a plurality of stringed and brass musical instruments each adapted to respond selectively to certain vibrations, anda rod connected to said armature which operatively engages said bodies to vibrate the bodies sonorously. v .20. In sound reproducing mechanimn, a

source of telephonic current, a plurality of resonant bodies of different timbre, and means'vibrated .by said telephonic current and operatively associated with said bodies for causing each body to vibrate sonorously in response to certain of said vibrations.

21. In, sound reproducing mechanism, a source of telephonic current, a plurality of stringedand brass musical instruments, and

means vibrated by said telephonic current and operatively associated with the instruments for causing each instrument to vibrate sonorously in response to certain selected vibrations. I

22. In sound reproducing mechanism, a phonograph stylus, means for producing a telephonic current from the vibrations of the stylus, a plurality of stringed and brass instruments each adapted to respond selective- 1y to vibrations of definite character, and

means vibrated by saidtelephonic current and operatively associated with said bodies for causing each body to vibrate sonorously in response to certain of said vibrations.

23. In sound reproducing mechanism, a phonograph stylus, means for producing a telephonic current from the Vibrations of the stylus, an electro-1nagnet,- means for energizing the magnet in response to the telephonic current, an armature for the magnet, a plurality of stringed and brass instruments adapted to respond selectively to certain vibrations, and means connecting said armature to said bodies for causing the bodies to vibrate sonorously.

CHARLES S. BABCOCK. 

